Abstract: An optical lens system includes a first lens barrel, a second lens barrel, multiple lenses and multiple fixing components. The first barrel contains a first lens disposing space and a first outer ring part surrounding the first lens disposing space. The first outer ring part is formed with indentations. Additionally, the second barrel contains a second lens disposing space and a second outer ring part, which surrounds the second lens disposing space. The second outer ring part is formed with protrusions. The second outer ring part is engaged to the first outer ring part, the protrusions is inserted to the indentations with loose fit. Furthermore, the lenses are disposed in the first lens disposing space and the second lens disposing space respectively. The fixing components are disposed on the first outer ring part and the second outer ring part to affix these two barrels with each other.